/* * Copyright © 2012 Intel Corporation * * Permission is hereby granted, free of charge, to any person obtaining a * copy of this software and associated documentation files (the "Software"), * to deal in the Software without restriction, including without limitation * the rights to use, copy, modify, merge, publish, distribute, sublicense, * and/or sell copies of the Software, and to permit persons to whom the * Software is furnished to do so, subject to the following conditions: * * The above copyright notice and this permission notice (including the next * paragraph) shall be included in all copies or substantial portions of the * Software. * * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER * DEALINGS IN THE SOFTWARE. */ /** * \file link_varyings.cpp * * Linker functions related specifically to linking varyings between shader * stages. */ #include "main/mtypes.h" #include "glsl_symbol_table.h" #include "glsl_parser_extras.h" #include "ir_optimization.h" #include "linker.h" #include "link_varyings.h" #include "main/macros.h" #include "program/hash_table.h" #include "program.h" /** * Validate that outputs from one stage match inputs of another */ void cross_validate_outputs_to_inputs(struct gl_shader_program *prog, gl_shader *producer, gl_shader *consumer) { glsl_symbol_table parameters; const char *const producer_stage = _mesa_glsl_shader_target_name(producer->Type); const char *const consumer_stage = _mesa_glsl_shader_target_name(consumer->Type); /* Find all shader outputs in the "producer" stage. */ foreach_list(node, producer->ir) { ir_variable *const var = ((ir_instruction *) node)->as_variable(); if ((var == NULL) || (var->mode != ir_var_shader_out)) continue; parameters.add_variable(var); } /* Find all shader inputs in the "consumer" stage. Any variables that have * matching outputs already in the symbol table must have the same type and * qualifiers. * * Exception: if the consumer is the geometry shader, then the inputs * should be arrays and the type of the array element should match the type * of the corresponding producer output. */ foreach_list(node, consumer->ir) { ir_variable *const input = ((ir_instruction *) node)->as_variable(); if ((input == NULL) || (input->mode != ir_var_shader_in)) continue; ir_variable *const output = parameters.get_variable(input->name); if (output != NULL) { /* Check that the types match between stages. */ const glsl_type *type_to_match = input->type; if (consumer->Type == GL_GEOMETRY_SHADER) { assert(type_to_match->is_array()); /* Enforced by ast_to_hir */ type_to_match = type_to_match->element_type(); } if (type_to_match != output->type) { /* There is a bit of a special case for gl_TexCoord. This * built-in is unsized by default. Applications that variable * access it must redeclare it with a size. There is some * language in the GLSL spec that implies the fragment shader * and vertex shader do not have to agree on this size. Other * driver behave this way, and one or two applications seem to * rely on it. * * Neither declaration needs to be modified here because the array * sizes are fixed later when update_array_sizes is called. * * From page 48 (page 54 of the PDF) of the GLSL 1.10 spec: * * "Unlike user-defined varying variables, the built-in * varying variables don't have a strict one-to-one * correspondence between the vertex language and the * fragment language." */ if (!output->type->is_array() || (strncmp("gl_", output->name, 3) != 0)) { linker_error(prog, "%s shader output `%s' declared as type `%s', " "but %s shader input declared as type `%s'\n", producer_stage, output->name, output->type->name, consumer_stage, input->type->name); return; } } /* Check that all of the qualifiers match between stages. */ if (input->centroid != output->centroid) { linker_error(prog, "%s shader output `%s' %s centroid qualifier, " "but %s shader input %s centroid qualifier\n", producer_stage, output->name, (output->centroid) ? "has" : "lacks", consumer_stage, (input->centroid) ? "has" : "lacks"); return; } if (input->invariant != output->invariant) { linker_error(prog, "%s shader output `%s' %s invariant qualifier, " "but %s shader input %s invariant qualifier\n", producer_stage, output->name, (output->invariant) ? "has" : "lacks", consumer_stage, (input->invariant) ? "has" : "lacks"); return; } if (input->interpolation != output->interpolation) { linker_error(prog, "%s shader output `%s' specifies %s " "interpolation qualifier, " "but %s shader input specifies %s " "interpolation qualifier\n", producer_stage, output->name, output->interpolation_string(), consumer_stage, input->interpolation_string()); return; } } } } /** * Initialize this object based on a string that was passed to * glTransformFeedbackVaryings. * * If the input is mal-formed, this call still succeeds, but it sets * this->var_name to a mal-formed input, so tfeedback_decl::find_output_var() * will fail to find any matching variable. */ void tfeedback_decl::init(struct gl_context *ctx, struct gl_shader_program *prog, const void *mem_ctx, const char *input) { /* We don't have to be pedantic about what is a valid GLSL variable name, * because any variable with an invalid name can't exist in the IR anyway. */ this->location = -1; this->orig_name = input; this->is_clip_distance_mesa = false; this->skip_components = 0; this->next_buffer_separator = false; this->matched_candidate = NULL; if (ctx->Extensions.ARB_transform_feedback3) { /* Parse gl_NextBuffer. */ if (strcmp(input, "gl_NextBuffer") == 0) { this->next_buffer_separator = true; return; } /* Parse gl_SkipComponents. */ if (strcmp(input, "gl_SkipComponents1") == 0) this->skip_components = 1; else if (strcmp(input, "gl_SkipComponents2") == 0) this->skip_components = 2; else if (strcmp(input, "gl_SkipComponents3") == 0) this->skip_components = 3; else if (strcmp(input, "gl_SkipComponents4") == 0) this->skip_components = 4; if (this->skip_components) return; } /* Parse a declaration. */ const char *base_name_end; long subscript = parse_program_resource_name(input, &base_name_end); this->var_name = ralloc_strndup(mem_ctx, input, base_name_end - input); if (subscript >= 0) { this->array_subscript = subscript; this->is_subscripted = true; } else { this->is_subscripted = false; } /* For drivers that lower gl_ClipDistance to gl_ClipDistanceMESA, this * class must behave specially to account for the fact that gl_ClipDistance * is converted from a float[8] to a vec4[2]. */ if (ctx->ShaderCompilerOptions[MESA_SHADER_VERTEX].LowerClipDistance && strcmp(this->var_name, "gl_ClipDistance") == 0) { this->is_clip_distance_mesa = true; } } /** * Determine whether two tfeedback_decl objects refer to the same variable and * array index (if applicable). */ bool tfeedback_decl::is_same(const tfeedback_decl &x, const tfeedback_decl &y) { assert(x.is_varying() && y.is_varying()); if (strcmp(x.var_name, y.var_name) != 0) return false; if (x.is_subscripted != y.is_subscripted) return false; if (x.is_subscripted && x.array_subscript != y.array_subscript) return false; return true; } /** * Assign a location for this tfeedback_decl object based on the transform * feedback candidate found by find_candidate. * * If an error occurs, the error is reported through linker_error() and false * is returned. */ bool tfeedback_decl::assign_location(struct gl_context *ctx, struct gl_shader_program *prog) { assert(this->is_varying()); unsigned fine_location = this->matched_candidate->toplevel_var->location * 4 + this->matched_candidate->toplevel_var->location_frac + this->matched_candidate->offset; if (this->matched_candidate->type->is_array()) { /* Array variable */ const unsigned matrix_cols = this->matched_candidate->type->fields.array->matrix_columns; const unsigned vector_elements = this->matched_candidate->type->fields.array->vector_elements; unsigned actual_array_size = this->is_clip_distance_mesa ? prog->Vert.ClipDistanceArraySize : this->matched_candidate->type->array_size(); if (this->is_subscripted) { /* Check array bounds. */ if (this->array_subscript >= actual_array_size) { linker_error(prog, "Transform feedback varying %s has index " "%i, but the array size is %u.", this->orig_name, this->array_subscript, actual_array_size); return false; } unsigned array_elem_size = this->is_clip_distance_mesa ? 1 : vector_elements * matrix_cols; fine_location += array_elem_size * this->array_subscript; this->size = 1; } else { this->size = actual_array_size; } this->vector_elements = vector_elements; this->matrix_columns = matrix_cols; if (this->is_clip_distance_mesa) this->type = GL_FLOAT; else this->type = this->matched_candidate->type->fields.array->gl_type; } else { /* Regular variable (scalar, vector, or matrix) */ if (this->is_subscripted) { linker_error(prog, "Transform feedback varying %s requested, " "but %s is not an array.", this->orig_name, this->var_name); return false; } this->size = 1; this->vector_elements = this->matched_candidate->type->vector_elements; this->matrix_columns = this->matched_candidate->type->matrix_columns; this->type = this->matched_candidate->type->gl_type; } this->location = fine_location / 4; this->location_frac = fine_location % 4; /* From GL_EXT_transform_feedback: * A program will fail to link if: * * * the total number of components to capture in any varying * variable in is greater than the constant * MAX_TRANSFORM_FEEDBACK_SEPARATE_COMPONENTS_EXT and the * buffer mode is SEPARATE_ATTRIBS_EXT; */ if (prog->TransformFeedback.BufferMode == GL_SEPARATE_ATTRIBS && this->num_components() > ctx->Const.MaxTransformFeedbackSeparateComponents) { linker_error(prog, "Transform feedback varying %s exceeds " "MAX_TRANSFORM_FEEDBACK_SEPARATE_COMPONENTS.", this->orig_name); return false; } return true; } unsigned tfeedback_decl::get_num_outputs() const { if (!this->is_varying()) { return 0; } return (this->num_components() + this->location_frac + 3)/4; } /** * Update gl_transform_feedback_info to reflect this tfeedback_decl. * * If an error occurs, the error is reported through linker_error() and false * is returned. */ bool tfeedback_decl::store(struct gl_context *ctx, struct gl_shader_program *prog, struct gl_transform_feedback_info *info, unsigned buffer, const unsigned max_outputs) const { assert(!this->next_buffer_separator); /* Handle gl_SkipComponents. */ if (this->skip_components) { info->BufferStride[buffer] += this->skip_components; return true; } /* From GL_EXT_transform_feedback: * A program will fail to link if: * * * the total number of components to capture is greater than * the constant MAX_TRANSFORM_FEEDBACK_INTERLEAVED_COMPONENTS_EXT * and the buffer mode is INTERLEAVED_ATTRIBS_EXT. */ if (prog->TransformFeedback.BufferMode == GL_INTERLEAVED_ATTRIBS && info->BufferStride[buffer] + this->num_components() > ctx->Const.MaxTransformFeedbackInterleavedComponents) { linker_error(prog, "The MAX_TRANSFORM_FEEDBACK_INTERLEAVED_COMPONENTS " "limit has been exceeded."); return false; } unsigned location = this->location; unsigned location_frac = this->location_frac; unsigned num_components = this->num_components(); while (num_components > 0) { unsigned output_size = MIN2(num_components, 4 - location_frac); assert(info->NumOutputs < max_outputs); info->Outputs[info->NumOutputs].ComponentOffset = location_frac; info->Outputs[info->NumOutputs].OutputRegister = location; info->Outputs[info->NumOutputs].NumComponents = output_size; info->Outputs[info->NumOutputs].OutputBuffer = buffer; info->Outputs[info->NumOutputs].DstOffset = info->BufferStride[buffer]; ++info->NumOutputs; info->BufferStride[buffer] += output_size; num_components -= output_size; location++; location_frac = 0; } info->Varyings[info->NumVarying].Name = ralloc_strdup(prog, this->orig_name); info->Varyings[info->NumVarying].Type = this->type; info->Varyings[info->NumVarying].Size = this->size; info->NumVarying++; return true; } const tfeedback_candidate * tfeedback_decl::find_candidate(gl_shader_program *prog, hash_table *tfeedback_candidates) { const char *name = this->is_clip_distance_mesa ? "gl_ClipDistanceMESA" : this->var_name; this->matched_candidate = (const tfeedback_candidate *) hash_table_find(tfeedback_candidates, name); if (!this->matched_candidate) { /* From GL_EXT_transform_feedback: * A program will fail to link if: * * * any variable name specified in the array is not * declared as an output in the geometry shader (if present) or * the vertex shader (if no geometry shader is present); */ linker_error(prog, "Transform feedback varying %s undeclared.", this->orig_name); } return this->matched_candidate; } /** * Parse all the transform feedback declarations that were passed to * glTransformFeedbackVaryings() and store them in tfeedback_decl objects. * * If an error occurs, the error is reported through linker_error() and false * is returned. */ bool parse_tfeedback_decls(struct gl_context *ctx, struct gl_shader_program *prog, const void *mem_ctx, unsigned num_names, char **varying_names, tfeedback_decl *decls) { for (unsigned i = 0; i < num_names; ++i) { decls[i].init(ctx, prog, mem_ctx, varying_names[i]); if (!decls[i].is_varying()) continue; /* From GL_EXT_transform_feedback: * A program will fail to link if: * * * any two entries in the array specify the same varying * variable; * * We interpret this to mean "any two entries in the array * specify the same varying variable and array index", since transform * feedback of arrays would be useless otherwise. */ for (unsigned j = 0; j < i; ++j) { if (!decls[j].is_varying()) continue; if (tfeedback_decl::is_same(decls[i], decls[j])) { linker_error(prog, "Transform feedback varying %s specified " "more than once.", varying_names[i]); return false; } } } return true; } /** * Store transform feedback location assignments into * prog->LinkedTransformFeedback based on the data stored in tfeedback_decls. * * If an error occurs, the error is reported through linker_error() and false * is returned. */ bool store_tfeedback_info(struct gl_context *ctx, struct gl_shader_program *prog, unsigned num_tfeedback_decls, tfeedback_decl *tfeedback_decls) { bool separate_attribs_mode = prog->TransformFeedback.BufferMode == GL_SEPARATE_ATTRIBS; ralloc_free(prog->LinkedTransformFeedback.Varyings); ralloc_free(prog->LinkedTransformFeedback.Outputs); memset(&prog->LinkedTransformFeedback, 0, sizeof(prog->LinkedTransformFeedback)); prog->LinkedTransformFeedback.Varyings = rzalloc_array(prog, struct gl_transform_feedback_varying_info, num_tfeedback_decls); unsigned num_outputs = 0; for (unsigned i = 0; i < num_tfeedback_decls; ++i) num_outputs += tfeedback_decls[i].get_num_outputs(); prog->LinkedTransformFeedback.Outputs = rzalloc_array(prog, struct gl_transform_feedback_output, num_outputs); unsigned num_buffers = 0; if (separate_attribs_mode) { /* GL_SEPARATE_ATTRIBS */ for (unsigned i = 0; i < num_tfeedback_decls; ++i) { if (!tfeedback_decls[i].store(ctx, prog, &prog->LinkedTransformFeedback, num_buffers, num_outputs)) return false; num_buffers++; } } else { /* GL_INVERLEAVED_ATTRIBS */ for (unsigned i = 0; i < num_tfeedback_decls; ++i) { if (tfeedback_decls[i].is_next_buffer_separator()) { num_buffers++; continue; } if (!tfeedback_decls[i].store(ctx, prog, &prog->LinkedTransformFeedback, num_buffers, num_outputs)) return false; } num_buffers++; } assert(prog->LinkedTransformFeedback.NumOutputs == num_outputs); prog->LinkedTransformFeedback.NumBuffers = num_buffers; return true; } /** * Data structure recording the relationship between outputs of one shader * stage (the "producer") and inputs of another (the "consumer"). */ class varying_matches { public: varying_matches(bool disable_varying_packing, bool consumer_is_fs); ~varying_matches(); void record(ir_variable *producer_var, ir_variable *consumer_var); unsigned assign_locations(); void store_locations(unsigned producer_base, unsigned consumer_base) const; private: /** * If true, this driver disables varying packing, so all varyings need to * be aligned on slot boundaries, and take up a number of slots equal to * their number of matrix columns times their array size. */ const bool disable_varying_packing; /** * Enum representing the order in which varyings are packed within a * packing class. * * Currently we pack vec4's first, then vec2's, then scalar values, then * vec3's. This order ensures that the only vectors that are at risk of * having to be "double parked" (split between two adjacent varying slots) * are the vec3's. */ enum packing_order_enum { PACKING_ORDER_VEC4, PACKING_ORDER_VEC2, PACKING_ORDER_SCALAR, PACKING_ORDER_VEC3, }; static unsigned compute_packing_class(ir_variable *var); static packing_order_enum compute_packing_order(ir_variable *var); static int match_comparator(const void *x_generic, const void *y_generic); /** * Structure recording the relationship between a single producer output * and a single consumer input. */ struct match { /** * Packing class for this varying, computed by compute_packing_class(). */ unsigned packing_class; /** * Packing order for this varying, computed by compute_packing_order(). */ packing_order_enum packing_order; unsigned num_components; /** * The output variable in the producer stage. */ ir_variable *producer_var; /** * The input variable in the consumer stage. */ ir_variable *consumer_var; /** * The location which has been assigned for this varying. This is * expressed in multiples of a float, with the first generic varying * (i.e. the one referred to by VARYING_SLOT_VAR0) represented by the * value 0. */ unsigned generic_location; } *matches; /** * The number of elements in the \c matches array that are currently in * use. */ unsigned num_matches; /** * The number of elements that were set aside for the \c matches array when * it was allocated. */ unsigned matches_capacity; const bool consumer_is_fs; }; varying_matches::varying_matches(bool disable_varying_packing, bool consumer_is_fs) : disable_varying_packing(disable_varying_packing), consumer_is_fs(consumer_is_fs) { /* Note: this initial capacity is rather arbitrarily chosen to be large * enough for many cases without wasting an unreasonable amount of space. * varying_matches::record() will resize the array if there are more than * this number of varyings. */ this->matches_capacity = 8; this->matches = (match *) malloc(sizeof(*this->matches) * this->matches_capacity); this->num_matches = 0; } varying_matches::~varying_matches() { free(this->matches); } /** * Record the given producer/consumer variable pair in the list of variables * that should later be assigned locations. * * It is permissible for \c consumer_var to be NULL (this happens if a * variable is output by the producer and consumed by transform feedback, but * not consumed by the consumer). * * If \c producer_var has already been paired up with a consumer_var, or * producer_var is part of fixed pipeline functionality (and hence already has * a location assigned), this function has no effect. * * Note: as a side effect this function may change the interpolation type of * \c producer_var, but only when the change couldn't possibly affect * rendering. */ void varying_matches::record(ir_variable *producer_var, ir_variable *consumer_var) { if (!producer_var->is_unmatched_generic_inout) { /* Either a location already exists for this variable (since it is part * of fixed functionality), or it has already been recorded as part of a * previous match. */ return; } if ((consumer_var == NULL && producer_var->type->contains_integer()) || !consumer_is_fs) { /* Since this varying is not being consumed by the fragment shader, its * interpolation type varying cannot possibly affect rendering. Also, * this variable is non-flat and is (or contains) an integer. * * lower_packed_varyings requires all integer varyings to flat, * regardless of where they appear. We can trivially satisfy that * requirement by changing the interpolation type to flat here. */ producer_var->centroid = false; producer_var->interpolation = INTERP_QUALIFIER_FLAT; if (consumer_var) { consumer_var->centroid = false; consumer_var->interpolation = INTERP_QUALIFIER_FLAT; } } if (this->num_matches == this->matches_capacity) { this->matches_capacity *= 2; this->matches = (match *) realloc(this->matches, sizeof(*this->matches) * this->matches_capacity); } this->matches[this->num_matches].packing_class = this->compute_packing_class(producer_var); this->matches[this->num_matches].packing_order = this->compute_packing_order(producer_var); if (this->disable_varying_packing) { unsigned slots = producer_var->type->is_array() ? (producer_var->type->length * producer_var->type->fields.array->matrix_columns) : producer_var->type->matrix_columns; this->matches[this->num_matches].num_components = 4 * slots; } else { this->matches[this->num_matches].num_components = producer_var->type->component_slots(); } this->matches[this->num_matches].producer_var = producer_var; this->matches[this->num_matches].consumer_var = consumer_var; this->num_matches++; producer_var->is_unmatched_generic_inout = 0; if (consumer_var) consumer_var->is_unmatched_generic_inout = 0; } /** * Choose locations for all of the variable matches that were previously * passed to varying_matches::record(). */ unsigned varying_matches::assign_locations() { /* Sort varying matches into an order that makes them easy to pack. */ qsort(this->matches, this->num_matches, sizeof(*this->matches), &varying_matches::match_comparator); unsigned generic_location = 0; for (unsigned i = 0; i < this->num_matches; i++) { /* Advance to the next slot if this varying has a different packing * class than the previous one, and we're not already on a slot * boundary. */ if (i > 0 && this->matches[i - 1].packing_class != this->matches[i].packing_class) { generic_location = ALIGN(generic_location, 4); } this->matches[i].generic_location = generic_location; generic_location += this->matches[i].num_components; } return (generic_location + 3) / 4; } /** * Update the producer and consumer shaders to reflect the locations * assignments that were made by varying_matches::assign_locations(). */ void varying_matches::store_locations(unsigned producer_base, unsigned consumer_base) const { for (unsigned i = 0; i < this->num_matches; i++) { ir_variable *producer_var = this->matches[i].producer_var; ir_variable *consumer_var = this->matches[i].consumer_var; unsigned generic_location = this->matches[i].generic_location; unsigned slot = generic_location / 4; unsigned offset = generic_location % 4; producer_var->location = producer_base + slot; producer_var->location_frac = offset; if (consumer_var) { assert(consumer_var->location == -1); consumer_var->location = consumer_base + slot; consumer_var->location_frac = offset; } } } /** * Compute the "packing class" of the given varying. This is an unsigned * integer with the property that two variables in the same packing class can * be safely backed into the same vec4. */ unsigned varying_matches::compute_packing_class(ir_variable *var) { /* Without help from the back-end, there is no way to pack together * variables with different interpolation types, because * lower_packed_varyings must choose exactly one interpolation type for * each packed varying it creates. * * However, we can safely pack together floats, ints, and uints, because: * * - varyings of base type "int" and "uint" must use the "flat" * interpolation type, which can only occur in GLSL 1.30 and above. * * - On platforms that support GLSL 1.30 and above, lower_packed_varyings * can store flat floats as ints without losing any information (using * the ir_unop_bitcast_* opcodes). * * Therefore, the packing class depends only on the interpolation type. */ unsigned packing_class = var->centroid ? 1 : 0; packing_class *= 4; packing_class += var->interpolation; return packing_class; } /** * Compute the "packing order" of the given varying. This is a sort key we * use to determine when to attempt to pack the given varying relative to * other varyings in the same packing class. */ varying_matches::packing_order_enum varying_matches::compute_packing_order(ir_variable *var) { const glsl_type *element_type = var->type; while (element_type->base_type == GLSL_TYPE_ARRAY) { element_type = element_type->fields.array; } switch (element_type->component_slots() % 4) { case 1: return PACKING_ORDER_SCALAR; case 2: return PACKING_ORDER_VEC2; case 3: return PACKING_ORDER_VEC3; case 0: return PACKING_ORDER_VEC4; default: assert(!"Unexpected value of vector_elements"); return PACKING_ORDER_VEC4; } } /** * Comparison function passed to qsort() to sort varyings by packing_class and * then by packing_order. */ int varying_matches::match_comparator(const void *x_generic, const void *y_generic) { const match *x = (const match *) x_generic; const match *y = (const match *) y_generic; if (x->packing_class != y->packing_class) return x->packing_class - y->packing_class; return x->packing_order - y->packing_order; } /** * Is the given variable a varying variable to be counted against the * limit in ctx->Const.MaxVarying? * This includes variables such as texcoords, colors and generic * varyings, but excludes variables such as gl_FrontFacing and gl_FragCoord. */ static bool is_varying_var(GLenum shaderType, const ir_variable *var) { /* Only fragment shaders will take a varying variable as an input */ if (shaderType == GL_FRAGMENT_SHADER && var->mode == ir_var_shader_in) { switch (var->location) { case VARYING_SLOT_POS: case VARYING_SLOT_FACE: case VARYING_SLOT_PNTC: return false; default: return true; } } return false; } /** * Visitor class that generates tfeedback_candidate structs describing all * possible targets of transform feedback. * * tfeedback_candidate structs are stored in the hash table * tfeedback_candidates, which is passed to the constructor. This hash table * maps varying names to instances of the tfeedback_candidate struct. */ class tfeedback_candidate_generator : public program_resource_visitor { public: tfeedback_candidate_generator(void *mem_ctx, hash_table *tfeedback_candidates) : mem_ctx(mem_ctx), tfeedback_candidates(tfeedback_candidates), toplevel_var(NULL), varying_floats(0) { } void process(ir_variable *var) { this->toplevel_var = var; this->varying_floats = 0; if (var->is_interface_instance()) program_resource_visitor::process(var->interface_type, var->interface_type->name); else program_resource_visitor::process(var); } private: virtual void visit_field(const glsl_type *type, const char *name, bool row_major) { assert(!type->is_record()); assert(!(type->is_array() && type->fields.array->is_record())); assert(!type->is_interface()); assert(!(type->is_array() && type->fields.array->is_interface())); (void) row_major; tfeedback_candidate *candidate = rzalloc(this->mem_ctx, tfeedback_candidate); candidate->toplevel_var = this->toplevel_var; candidate->type = type; candidate->offset = this->varying_floats; hash_table_insert(this->tfeedback_candidates, candidate, ralloc_strdup(this->mem_ctx, name)); this->varying_floats += type->component_slots(); } /** * Memory context used to allocate hash table keys and values. */ void * const mem_ctx; /** * Hash table in which tfeedback_candidate objects should be stored. */ hash_table * const tfeedback_candidates; /** * Pointer to the toplevel variable that is being traversed. */ ir_variable *toplevel_var; /** * Total number of varying floats that have been visited so far. This is * used to determine the offset to each varying within the toplevel * variable. */ unsigned varying_floats; }; /** * Assign locations for all variables that are produced in one pipeline stage * (the "producer") and consumed in the next stage (the "consumer"). * * Variables produced by the producer may also be consumed by transform * feedback. * * \param num_tfeedback_decls is the number of declarations indicating * variables that may be consumed by transform feedback. * * \param tfeedback_decls is a pointer to an array of tfeedback_decl objects * representing the result of parsing the strings passed to * glTransformFeedbackVaryings(). assign_location() will be called for * each of these objects that matches one of the outputs of the * producer. * * When num_tfeedback_decls is nonzero, it is permissible for the consumer to * be NULL. In this case, varying locations are assigned solely based on the * requirements of transform feedback. */ bool assign_varying_locations(struct gl_context *ctx, void *mem_ctx, struct gl_shader_program *prog, gl_shader *producer, gl_shader *consumer, unsigned num_tfeedback_decls, tfeedback_decl *tfeedback_decls) { const unsigned producer_base = VARYING_SLOT_VAR0; const unsigned consumer_base = VARYING_SLOT_VAR0; varying_matches matches(ctx->Const.DisableVaryingPacking, consumer && consumer->Type == GL_FRAGMENT_SHADER); hash_table *tfeedback_candidates = hash_table_ctor(0, hash_table_string_hash, hash_table_string_compare); hash_table *consumer_inputs = hash_table_ctor(0, hash_table_string_hash, hash_table_string_compare); hash_table *consumer_interface_inputs = hash_table_ctor(0, hash_table_string_hash, hash_table_string_compare); /* Operate in a total of three passes. * * 1. Assign locations for any matching inputs and outputs. * * 2. Mark output variables in the producer that do not have locations as * not being outputs. This lets the optimizer eliminate them. * * 3. Mark input variables in the consumer that do not have locations as * not being inputs. This lets the optimizer eliminate them. */ if (consumer) { foreach_list(node, consumer->ir) { ir_variable *const input_var = ((ir_instruction *) node)->as_variable(); if ((input_var != NULL) && (input_var->mode == ir_var_shader_in)) { if (input_var->interface_type != NULL) { char *const iface_field_name = ralloc_asprintf(mem_ctx, "%s.%s", input_var->interface_type->name, input_var->name); hash_table_insert(consumer_interface_inputs, input_var, iface_field_name); } else { hash_table_insert(consumer_inputs, input_var, ralloc_strdup(mem_ctx, input_var->name)); } } } } foreach_list(node, producer->ir) { ir_variable *const output_var = ((ir_instruction *) node)->as_variable(); if ((output_var == NULL) || (output_var->mode != ir_var_shader_out)) continue; tfeedback_candidate_generator g(mem_ctx, tfeedback_candidates); g.process(output_var); ir_variable *input_var; if (output_var->interface_type != NULL) { char *const iface_field_name = ralloc_asprintf(mem_ctx, "%s.%s", output_var->interface_type->name, output_var->name); input_var = (ir_variable *) hash_table_find(consumer_interface_inputs, iface_field_name); } else { input_var = (ir_variable *) hash_table_find(consumer_inputs, output_var->name); } if (input_var && input_var->mode != ir_var_shader_in) input_var = NULL; if (input_var) { matches.record(output_var, input_var); } } for (unsigned i = 0; i < num_tfeedback_decls; ++i) { if (!tfeedback_decls[i].is_varying()) continue; const tfeedback_candidate *matched_candidate = tfeedback_decls[i].find_candidate(prog, tfeedback_candidates); if (matched_candidate == NULL) { hash_table_dtor(tfeedback_candidates); hash_table_dtor(consumer_inputs); hash_table_dtor(consumer_interface_inputs); return false; } if (matched_candidate->toplevel_var->is_unmatched_generic_inout) matches.record(matched_candidate->toplevel_var, NULL); } const unsigned slots_used = matches.assign_locations(); matches.store_locations(producer_base, consumer_base); for (unsigned i = 0; i < num_tfeedback_decls; ++i) { if (!tfeedback_decls[i].is_varying()) continue; if (!tfeedback_decls[i].assign_location(ctx, prog)) { hash_table_dtor(tfeedback_candidates); hash_table_dtor(consumer_inputs); hash_table_dtor(consumer_interface_inputs); return false; } } hash_table_dtor(tfeedback_candidates); hash_table_dtor(consumer_inputs); hash_table_dtor(consumer_interface_inputs); if (ctx->Const.DisableVaryingPacking) { /* Transform feedback code assumes varyings are packed, so if the driver * has disabled varying packing, make sure it does not support transform * feedback. */ assert(!ctx->Extensions.EXT_transform_feedback); } else { lower_packed_varyings(mem_ctx, producer_base, slots_used, ir_var_shader_out, producer); if (consumer) { lower_packed_varyings(mem_ctx, consumer_base, slots_used, ir_var_shader_in, consumer); } } if (consumer) { foreach_list(node, consumer->ir) { ir_variable *const var = ((ir_instruction *) node)->as_variable(); if (var && var->mode == ir_var_shader_in && var->is_unmatched_generic_inout) { if (prog->Version <= 120) { /* On page 25 (page 31 of the PDF) of the GLSL 1.20 spec: * * Only those varying variables used (i.e. read) in * the fragment shader executable must be written to * by the vertex shader executable; declaring * superfluous varying variables in a vertex shader is * permissible. * * We interpret this text as meaning that the VS must * write the variable for the FS to read it. See * "glsl1-varying read but not written" in piglit. */ linker_error(prog, "%s shader varying %s not written " "by %s shader\n.", _mesa_glsl_shader_target_name(consumer->Type), var->name, _mesa_glsl_shader_target_name(producer->Type)); } /* An 'in' variable is only really a shader input if its * value is written by the previous stage. */ var->mode = ir_var_auto; } } } return true; } bool check_against_varying_limit(struct gl_context *ctx, struct gl_shader_program *prog, gl_shader *consumer) { unsigned varying_vectors = 0; foreach_list(node, consumer->ir) { ir_variable *const var = ((ir_instruction *) node)->as_variable(); if (var && var->mode == ir_var_shader_in && is_varying_var(consumer->Type, var)) { /* The packing rules used for vertex shader inputs are also * used for fragment shader inputs. */ varying_vectors += var->type->count_attribute_slots(); } } if (ctx->API == API_OPENGLES2 || prog->IsES) { if (varying_vectors > ctx->Const.MaxVarying) { linker_error(prog, "shader uses too many varying vectors " "(%u > %u)\n", varying_vectors, ctx->Const.MaxVarying); return false; } } else { const unsigned float_components = varying_vectors * 4; if (float_components > ctx->Const.MaxVarying * 4) { linker_error(prog, "shader uses too many varying components " "(%u > %u)\n", float_components, ctx->Const.MaxVarying * 4); return false; } } return true; }